Kinetis K64F output pins are connecting to input pins of SN74LS07 buffer.
The Vcc of SN74LS07 is 5V.
It works normally.
However, I am worried about the reverse current to K64F Vdd (3.3V) from SN74LS07 input pin.
SN74LS07 datasheet says "I_IH is 20uA, I_IL is -0.2mA".
Are these value no problem for K64F ?
I had thought that All digital I/O pins are 5V tolerant.
But some people say that "The Kinetis Port pins are only 5V tolerant as inputs. The outputs are not 5V tolerant." in other threads.
Which is true?